A sheet processing apparatus is known which comprises a heating apparatus used in a fixing device for fixing a visualized image with a developing material, that is, a color material, on a sheet and used in an erasing apparatus for erasing the color of the visualized image to reuse the sheet.
Generally, the heating apparatus comprises a heating mechanism including, for example, a heat roller having a heat source and a press roller for pressing a sheet having the color material against the heat roller as the sheet is conveyed, to thereby carry out heating processing on the sheet.